you can add a comment to instruct clj-kondo to ignore that problem for :clj

#_{:clj-kondo/ignore #?(:clj [:unused-binding] :cljs [])}
(defn foo
  [x]
  #?(:clj 1 :cljs x))

in fact this is not a false warning report. for cljc files clj-kondo is trying to analyze all contexts (clj and cljs) and your snippet has unused binding for clj scope

more info — https://cljdoc.org/d/clj-kondo/clj-kondo/2021.02.13/doc/configuration#ignore-warnings-in-an-expression

Thanks for the input @U04V4KLKC. It would be nice if I could configure the lint reports so that:

#_{:clj-kondo/ignore #?(:clj [:unused-binding] :cljs [])}
(defn foo
  [x]
  #?(:clj 1 :cljs x))

@U191H9E5C Why would you disable the warning for one language and not the other?

You can simply disable unused-binding warnings for the entire namespace

We have a tree of cljc code containing uix components, which we render server-side and subsequently render in a "rehydrated" context where cljs logic kicks-in. A number of our functions have parameters that are only referenced in the :cljs expressions within the functions, hence the clj-kondo warnings I showed in the example above are prevalent.

Most of the time I don't care if a parameter is used in either clj or cljs land, I only care if it isn't used anywhere in a function. Hopefully it makes sense.

Feel free to post an issue about this (and I will label it with the sponsor tag :))